1. Field of the Invention
The present invention relates to a Thermococcus mutant having an increased ability to produce hydrogen from formate and a method of producing hydrogen using the same.
2. Description of the Prior Art
The use of hydrogen in industrial areas has increased each year, and the use of hydrogen as a clean energy source for fuel cell vehicles and hydrogen power plants has gradually increased. Thus, it is expected that the supply of hydrogen will increase by geometric progression. As the value of hydrogen as clean energy increases and a method capable of steadily supplying a large amount of hydrogen is receiving attention, studies on methods for producing hydrogen have been actively conducted.
Hydrogen energy has an energy density that is three times higher than that of petroleum while it does not emit environmentally harmful materials such as carbon dioxide, NOx and SOx, and thus it receives attention as energy that will substitute for fossil fuels.
Conventional method for producing hydrogen include the electrolysis of water, the thermal-cracking or steam reforming of natural gas or naphtha, etc. However, such methods have problems in that it is required to form the conditions of high-temperature and high-pressure using fossil fuels and in that a gas mixture containing carbon monoxide is generated and it is difficult to remove carbon monoxide from this gas mixture.
On the other hand, biological methods of producing hydrogen using microorganisms have advantages in that it is not required to form the conditions of high-temperature and high-pressure by the use of energy and in that the gas produced contains no carbon monoxide. Such biological methods for producing hydrogen can be largely divided into methods based on the use of photosynthetic microorganisms and methods based on the use of non-photosynthetic microorganisms (mainly anaerobic microorganisms). Examples of the former include Korean Patent Registration No. 10-0680624, entitled “Method of producing hydrogen using the photosynthetic bacterial strain Rhodobacter sphaeroides having an excellent ability to produce hydrogen at high salt concentration”.
However, the development of technology for high-concentration culture of photosynthetic bacteria that use light as an energy source is not yet sufficient, and conventional photosynthetic bacteria severely inhibit a substrate under high partial pressure. In addition, there is a disadvantage in that these photosynthetic bacteria can show the ability to produce hydrogen even in the presence of light.
Thus, there have been continued attempts to hydrogen using microorganisms capable of hydrogen using organic carbon compounds. Examples of such attempts include Korean Patent Registration No. 10-0315663, entitled “Citrobacter sp. strain Y19 and production of hydrogen thereby”, and Korean Patent Registration No. 10-0315662, entitled “Rhodopseudomonas palustris P4 and production of hydrogen thereby”.
Korean Patent Publication No. 10-2011-0069744 discloses a FDH2-MFH2-MNH2 hydrogenase cluster and describes that fdh2-mfh2-mnh2 is important in producing hydrogen from formic acid.
Korean Patent Publication No. 10-2012-0103238 filed in the present inventors discloses a method of producing hydrogen using a Thermococcus sp. strain.
However, the role of F420-reducing hydrogenase in producing hydrogen from formic acid has not yet been reported. The present inventors increased the expression of F420-reducing hydrogenase (frh) in a Thermococcus sp. strain, based on the fact that F420-reducing hydrogenase (frh) is present immediately before the fdh2-mfh2-mnh2 cluster that produces hydrogen from formic acid, and as a result, the present inventors found that the production of hydrogen in the Thermococcus sp. strain was increased, thereby completing the present invention.